Hello there, Osr4gh,
I've read your question and I believe that a lot of people have encountered this problem including myself.
I have here some solutions that might help you solve your issue. Though, you forgot to mention the brand of your laptop and the operating system it's running on.
If you have a Netgear, Belkin, or a Linksys wireless router, you should have its manual. In that manual you will find out how to do a password reset and a hard reset on the router itself.
There are 2 ways where you can put a password. The first password is to set-up the router and the second password is to get your laptops/PC's connect to the router.
I believe the password you are talking about is the second one.
There are 3 types of encryption:
For you to check and verify which 1 you can use, you need to first check on your wireless adapter on the laptop you are using if it supports the type of encryption you want. Older laptops may not support WPA and WPA2 encryption so it's actually worth checking.
Assuming you are using a windows laptop, you can check on your wireless adapter in:
1. Click on your START button and click on CONTROL PANEL.
2. Click on HARDWARE AND SOUND in the control panel window.
Reminder: If your Control Panel is in Classic View, you can right away click twice on Device Manager.
3. In Hardware and Sound Window, double click on Device Manager to open.
4. Once Device Manager is open, look for Network adapters and click on the + sign. Do a right click on network/wireless adapter and select Properties.
5. The network/wireless adapter properties will appear and on the General tab you will see This device is working properly.
Reminder: If there is a problem with your network adapter, you can click on the Driver tab to check for details, update driver, and disable/uninstall driver.
Also, you should remember that passwords are case sensitive so you should be very careful in typing your password.
Finally, after checking your network adapter supports the type of encryption you are using and that it is working properly then there shouldn't be any problem. Just make sure you type in the correct password (case sensitive).
You mentioned that your dad and older brother are using the wireless connection too. Don't forget to inform them that you're going to do a password reset on your router and that if you decide to choose another password, you will give it to them so they can connect to your wireless connection too.
Hope the information i presentation I presented here will help you solve the problem.